Polyimide film and sheet materials are well known and have long been used in applications requiring high temperature stability. Polyimide has proven itself to be chemically stable at high temperatures and in a variety of hostile atmospheres and environments. Films and sheets of polyimide have found wide acceptance in electrical and electronic applications, especially in applications wherein the polyimide will not be burned or, if burned, the presence of ash will not be detrimental.
The present invention provides an improved polyimide exhibiting most qualities of the polyimide of the prior art substantially unchanged and, also, exhibiting a uniform combustion front in an oxygen-rich atmosphere resulting in substantially ash-free combustion products.